Pull kgdb updates from Daniel Thompson:
"Changes for kgdb/kdb this cycle are dominated by a change from Sumit
that removes as small (256K) private heap from kdb. This is change
I've hoped for ever since I discovered how few users of this heap
remained in the kernel, so many thanks to Sumit for hunting these
down.
The other change is an incremental step towards SPDX headers"
* tag 'kgdb-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
kernel: debug: Convert to SPDX identifier
kdb: Rename members of struct kdbtab_t
kdb: Simplify kdb_defcmd macro logic
kdb: Get rid of redundant kdb_register_flags()
kdb: Rename struct defcmd_set to struct kdb_macro
kdb: Get rid of custom debug heap allocator
This reverts commit 9857a17f20.
That commit was completely broken, and I should have caught on to it
earlier. But happily, the kernel test robot noticed the breakage fairly
quickly.
The breakage is because "try_get_page()" is about avoiding the page
reference count overflow case, but is otherwise the exact same as a
plain "get_page()".
In contrast, "try_get_compound_head()" is an entirely different beast,
and uses __page_cache_add_speculative() because it's not just about the
page reference count, but also about possibly racing with the underlying
page going away.
So all the commentary about how
"try_get_page() has fallen a little behind in terms of maintenance,
try_get_compound_head() handles speculative page references more
thoroughly"
was just completely wrong: yes, try_get_compound_head() handles
speculative page references, but the point is that try_get_page() does
not, and must not.
So there's no lack of maintainance - there are fundamentally different
semantics.
A speculative page reference would be entirely wrong in "get_page()",
and it's entirely wrong in "try_get_page()". It's not about
speculation, it's purely about "uhhuh, you can't get this page because
you've tried to increment the reference count too much already".
The reason the kernel test robot noticed this bug was that it hit the
VM_BUG_ON() in __page_cache_add_speculative(), which is all about
verifying that the context of any speculative page access is correct.
But since that isn't what try_get_page() is all about, the VM_BUG_ON()
tests things that are not correct to test for try_get_page().
Reported-by: kernel test robot <oliver.sang@intel.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull libata fixes from Jens Axboe:
"Fixes for queued trim on certain Samsung SSDs, in conjunction with
certain ATI controllers"
* tag 'libata-5.15-2021-09-05' of git://git.kernel.dk/linux-block:
libata: Add ATA_HORKAGE_NO_NCQ_ON_ATI for Samsung 860 and 870 SSD.
libata: add ATA_HORKAGE_NO_NCQ_TRIM for Samsung 860 and 870 SSDs
Pull io_uring fixes from Jens Axboe:
"As sometimes happens, two reports came in around the merge window open
that led to some fixes. Hence this one is a bit bigger than usual
followup fixes, but most of it will be going towards stable, outside
of the fixes that are addressing regressions from this merge window.
In detail:
- postgres is a heavy user of signals between tasks, and if we're
unlucky this can interfere with io-wq worker creation. Make sure
we're resilient against unrelated signal handling. This set of
changes also includes hardening against allocation failures, which
could previously had led to stalls.
- Some use cases that end up having a mix of bounded and unbounded
work would have starvation issues related to that. Split the
pending work lists to handle that better.
- Completion trace int -> unsigned -> long fix
- Fix issue with REGISTER_IOWQ_MAX_WORKERS and SQPOLL
- Fix regression with hash wait lock in this merge window
- Fix retry issued on block devices (Ming)
- Fix regression with links in this merge window (Pavel)
- Fix race with multi-shot poll and completions (Xiaoguang)
- Ensure regular file IO doesn't inadvertently skip completion
batching (Pavel)
- Ensure submissions are flushed after running task_work (Pavel)"
* tag 'for-5.15/io_uring-2021-09-04' of git://git.kernel.dk/linux-block:
io_uring: io_uring_complete() trace should take an integer
io_uring: fix possible poll event lost in multi shot mode
io_uring: prolong tctx_task_work() with flushing
io_uring: don't disable kiocb_done() CQE batching
io_uring: ensure IORING_REGISTER_IOWQ_MAX_WORKERS works with SQPOLL
io-wq: make worker creation resilient against signals
io-wq: get rid of FIXED worker flag
io-wq: only exit on fatal signals
io-wq: split bounded and unbounded work into separate lists
io-wq: fix queue stalling race
io_uring: don't submit half-prepared drain request
io_uring: fix queueing half-created requests
io-wq: ensure that hash wait lock is IRQ disabling
io_uring: retry in case of short read on block device
io_uring: IORING_OP_WRITE needs hash_reg_file set
io-wq: fix race between adding work and activating a free worker
Pull tracing updates from Steven Rostedt:
- simplify the Kconfig use of FTRACE and TRACE_IRQFLAGS_SUPPORT
- bootconfig can now start histograms
- bootconfig supports group/all enabling
- histograms now can put values in linear size buckets
- execnames can be passed to synthetic events
- introduce "event probes" that attach to other events and can retrieve
data from pointers of fields, or record fields as different types (a
pointer to a string as a string instead of just a hex number)
- various fixes and clean ups
* tag 'trace-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (35 commits)
tracing/doc: Fix table format in histogram code
selftests/ftrace: Add selftest for testing duplicate eprobes and kprobes
selftests/ftrace: Add selftest for testing eprobe events on synthetic events
selftests/ftrace: Add test case to test adding and removing of event probe
selftests/ftrace: Fix requirement check of README file
selftests/ftrace: Add clear_dynamic_events() to test cases
tracing: Add a probe that attaches to trace events
tracing/probes: Reject events which have the same name of existing one
tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs
tracing/probe: Change traceprobe_set_print_fmt() to take a type
tracing/probes: Use struct_size() instead of defining custom macros
tracing/probes: Allow for dot delimiter as well as slash for system names
tracing/probe: Have traceprobe_parse_probe_arg() take a const arg
tracing: Have dynamic events have a ref counter
tracing: Add DYNAMIC flag for dynamic events
tracing: Replace deprecated CPU-hotplug functions.
MAINTAINERS: Add an entry for os noise/latency
tracepoint: Fix kerneldoc comments
bootconfig/tracing/ktest: Update ktest example for boot-time tracing
tools/bootconfig: Use per-group/all enable option in ftrace2bconf script
...
Pull MAP_DENYWRITE removal from David Hildenbrand:
"Remove all in-tree usage of MAP_DENYWRITE from the kernel and remove
VM_DENYWRITE.
There are some (minor) user-visible changes:
- We no longer deny write access to shared libaries loaded via legacy
uselib(); this behavior matches modern user space e.g. dlopen().
- We no longer deny write access to the elf interpreter after exec
completed, treating it just like shared libraries (which it often
is).
- We always deny write access to the file linked via /proc/pid/exe:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) will fail if write access to the
file cannot be denied, and write access to the file will remain
denied until the link is effectivel gone (exec, termination,
sys_prctl(PR_SET_MM_MAP/EXE_FILE)) -- just as if exec'ing the file.
Cross-compiled for a bunch of architectures (alpha, microblaze, i386,
s390x, ...) and verified via ltp that especially the relevant tests
(i.e., creat07 and execve04) continue working as expected"
* tag 'denywrite-for-5.15' of git://github.com/davidhildenbrand/linux:
fs: update documentation of get_write_access() and friends
mm: ignore MAP_DENYWRITE in ksys_mmap_pgoff()
mm: remove VM_DENYWRITE
binfmt: remove in-tree usage of MAP_DENYWRITE
kernel/fork: always deny write access to current MM exe_file
kernel/fork: factor out replacing the current MM exe_file
binfmt: don't use MAP_DENYWRITE when loading shared libraries via uselib()
Pull f2fs updates from Jaegeuk Kim:
"In this cycle, we've addressed some performance issues such as lock
contention, misbehaving compress_cache, allowing extent_cache for
compressed files, and new sysfs to adjust ra_size for fadvise.
In order to diagnose the performance issues quickly, we also added an
iostat which shows the IO latencies periodically.
On the stability side, we've found two memory leakage cases in the
error path in compression flow. And, we've also fixed various corner
cases in fiemap, quota, checkpoint=disable, zstd, and so on.
Enhancements:
- avoid long checkpoint latency by releasing nat_tree_lock
- collect and show iostats periodically
- support extent_cache for compressed files
- add a sysfs entry to manage ra_size given fadvise(POSIX_FADV_SEQUENTIAL)
- report f2fs GC status via sysfs
- add discard_unit=%s in mount option to handle zoned device
Bug fixes:
- fix two memory leakages when an error happens in the compressed IO flow
- fix commpress_cache to get the right LBA
- fix fiemap to deal with compressed case correctly
- fix wrong EIO returns due to SBI_NEED_FSCK
- fix missing writes when enabling checkpoint back
- fix quota deadlock
- fix zstd level mount option
In addition to the above major updates, we've cleaned up several code
paths such as dio, unnecessary operations, debugfs/f2fs/status, sanity
check, and typos"
* tag 'f2fs-for-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jaegeuk/f2fs: (46 commits)
f2fs: should put a page beyond EOF when preparing a write
f2fs: deallocate compressed pages when error happens
f2fs: enable realtime discard iff device supports discard
f2fs: guarantee to write dirty data when enabling checkpoint back
f2fs: fix to unmap pages from userspace process in punch_hole()
f2fs: fix unexpected ENOENT comes from f2fs_map_blocks()
f2fs: fix to account missing .skipped_gc_rwsem
f2fs: adjust unlock order for cleanup
f2fs: Don't create discard thread when device doesn't support realtime discard
f2fs: rebuild nat_bits during umount
f2fs: introduce periodic iostat io latency traces
f2fs: separate out iostat feature
f2fs: compress: do sanity check on cluster
f2fs: fix description about main_blkaddr node
f2fs: convert S_IRUGO to 0444
f2fs: fix to keep compatibility of fault injection interface
f2fs: support fault injection for f2fs_kmem_cache_alloc()
f2fs: compress: allow write compress released file after truncate to zero
f2fs: correct comment in segment.h
f2fs: improve sbi status info in debugfs/f2fs/status
...
Pull NFS client updates from Anna Schumaker:
"New Features:
- Better client responsiveness when server isn't replying
- Use refcount_t in sunrpc rpc_client refcount tracking
- Add srcaddr and dst_port to the sunrpc sysfs info files
- Add basic support for connection sharing between servers with multiple NICs`
Bugfixes and Cleanups:
- Sunrpc tracepoint cleanups
- Disconnect after ib_post_send() errors to avoid deadlocks
- Fix for tearing down rpcrdma_reps
- Fix a potential pNFS layoutget livelock loop
- pNFS layout barrier fixes
- Fix a potential memory corruption in rpc_wake_up_queued_task_set_status()
- Fix reconnection locking
- Fix return value of get_srcport()
- Remove rpcrdma_post_sends()
- Remove pNFS dead code
- Remove copy size restriction for inter-server copies
- Overhaul the NFS callback service
- Clean up sunrpc TCP socket shutdowns
- Always provide aligned buffers to RPC read layers"
* tag 'nfs-for-5.15-1' of git://git.linux-nfs.org/projects/anna/linux-nfs: (39 commits)
NFS: Always provide aligned buffers to the RPC read layers
NFSv4.1 add network transport when session trunking is detected
SUNRPC enforce creation of no more than max_connect xprts
NFSv4 introduce max_connect mount options
SUNRPC add xps_nunique_destaddr_xprts to xprt_switch_info in sysfs
SUNRPC keep track of number of transports to unique addresses
NFSv3: Delete duplicate judgement in nfs3_async_handle_jukebox
SUNRPC: Tweak TCP socket shutdown in the RPC client
SUNRPC: Simplify socket shutdown when not reusing TCP ports
NFSv4.2: remove restriction of copy size for inter-server copy.
NFS: Clean up the synopsis of callback process_op()
NFS: Extract the xdr_init_encode/decode() calls from decode_compound
NFS: Remove unused callback void decoder
NFS: Add a private local dispatcher for NFSv4 callback operations
SUNRPC: Eliminate the RQ_AUTHERR flag
SUNRPC: Set rq_auth_stat in the pg_authenticate() callout
SUNRPC: Add svc_rqst::rq_auth_stat
SUNRPC: Add dst_port to the sysfs xprt info file
SUNRPC: Add srcaddr as a file in sysfs
sunrpc: Fix return value of get_srcport()
...
It currently takes a long, and while that's normally OK, the io_uring
limit is an int. Internally in io_uring it's an int, but sometimes it's
passed as a long. That can yield confusing results where a completions
seems to generate a huge result:
ou-sqp-1297-1298 [001] ...1 788.056371: io_uring_complete: ring 000000000e98e046, user_data 0x0, result 4294967171, cflags 0
which is due to -ECANCELED being stored in an unsigned, and then passed
in as a long. Using the right int type, the trace looks correct:
iou-sqp-338-339 [002] ...1 15.633098: io_uring_complete: ring 00000000e0ac60cf, user_data 0x0, result -125, cflags 0
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull Kbuild updates from Masahiro Yamada:
- Add -s option (strict mode) to merge_config.sh to make it fail when
any symbol is redefined.
- Show a warning if a different compiler is used for building external
modules.
- Infer --target from ARCH for CC=clang to let you cross-compile the
kernel without CROSS_COMPILE.
- Make the integrated assembler default (LLVM_IAS=1) for CC=clang.
- Add <linux/stdarg.h> to the kernel source instead of borrowing
<stdarg.h> from the compiler.
- Add Nick Desaulniers as a Kbuild reviewer.
- Drop stale cc-option tests.
- Fix the combination of CONFIG_TRIM_UNUSED_KSYMS and CONFIG_LTO_CLANG
to handle symbols in inline assembly.
- Show a warning if 'FORCE' is missing for if_changed rules.
- Various cleanups
* tag 'kbuild-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (39 commits)
kbuild: redo fake deps at include/ksym/*.h
kbuild: clean up objtool_args slightly
modpost: get the *.mod file path more simply
checkkconfigsymbols.py: Fix the '--ignore' option
kbuild: merge vmlinux_link() between ARCH=um and other architectures
kbuild: do not remove 'linux' link in scripts/link-vmlinux.sh
kbuild: merge vmlinux_link() between the ordinary link and Clang LTO
kbuild: remove stale *.symversions
kbuild: remove unused quiet_cmd_update_lto_symversions
gen_compile_commands: extract compiler command from a series of commands
x86: remove cc-option-yn test for -mtune=
arc: replace cc-option-yn uses with cc-option
s390: replace cc-option-yn uses with cc-option
ia64: move core-y in arch/ia64/Makefile to arch/ia64/Kbuild
sparc: move the install rule to arch/sparc/Makefile
security: remove unneeded subdir-$(CONFIG_...)
kbuild: sh: remove unused install script
kbuild: Fix 'no symbols' warning when CONFIG_TRIM_UNUSD_KSYMS=y
kbuild: Switch to 'f' variants of integrated assembler flag
kbuild: Shuffle blank line to improve comment meaning
...
Pull iommu updates from Joerg Roedel:
- New DART IOMMU driver for Apple Silicon M1 chips
- Optimizations for iommu_[map/unmap] performance
- Selective TLB flush support for the AMD IOMMU driver to make it more
efficient on emulated IOMMUs
- Rework IOVA setup and default domain type setting to move more code
out of IOMMU drivers and to support runtime switching between certain
types of default domains
- VT-d Updates from Lu Baolu:
- Update the virtual command related registers
- Enable Intel IOMMU scalable mode by default
- Preset A/D bits for user space DMA usage
- Allow devices to have more than 32 outstanding PRs
- Various cleanups
- ARM SMMU Updates from Will Deacon:
SMMUv3:
- Minor optimisation to avoid zeroing struct members on CMD submission
- Increased use of batched commands to reduce submission latency
- Refactoring in preparation for ECMDQ support
SMMUv2:
- Fix races when probing devices with identical StreamIDs
- Optimise walk cache flushing for Qualcomm implementations
- Allow deep sleep states for some Qualcomm SoCs with shared clocks
- Various smaller optimizations, cleanups, and fixes
* tag 'iommu-updates-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (85 commits)
iommu/io-pgtable: Abstract iommu_iotlb_gather access
iommu/arm-smmu: Fix missing unlock on error in arm_smmu_device_group()
iommu/vt-d: Add present bit check in pasid entry setup helpers
iommu/vt-d: Use pasid_pte_is_present() helper function
iommu/vt-d: Drop the kernel doc annotation
iommu/vt-d: Allow devices to have more than 32 outstanding PRs
iommu/vt-d: Preset A/D bits for user space DMA usage
iommu/vt-d: Enable Intel IOMMU scalable mode by default
iommu/vt-d: Refactor Kconfig a bit
iommu/vt-d: Remove unnecessary oom message
iommu/vt-d: Update the virtual command related registers
iommu: Allow enabling non-strict mode dynamically
iommu: Merge strictness and domain type configs
iommu: Only log strictness for DMA domains
iommu: Expose DMA domain strictness via sysfs
iommu: Express DMA strictness via the domain type
iommu/vt-d: Prepare for multiple DMA domain types
iommu/arm-smmu: Prepare for multiple DMA domain types
iommu/amd: Prepare for multiple DMA domain types
iommu: Introduce explicit type for non-strict DMA domains
...
Pull swiotlb updates from Konrad Rzeszutek Wilk:
"A new feature called restricted DMA pools. It allows SWIOTLB to
utilize per-device (or per-platform) allocated memory pools instead of
using the global one.
The first big user of this is ARM Confidential Computing where the
memory for DMA operations can be set per platform"
* 'stable/for-linus-5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb: (23 commits)
swiotlb: use depends on for DMA_RESTRICTED_POOL
of: restricted dma: Don't fail device probe on rmem init failure
of: Move of_dma_set_restricted_buffer() into device.c
powerpc/svm: Don't issue ultracalls if !mem_encrypt_active()
s390/pv: fix the forcing of the swiotlb
swiotlb: Free tbl memory in swiotlb_exit()
swiotlb: Emit diagnostic in swiotlb_exit()
swiotlb: Convert io_default_tlb_mem to static allocation
of: Return success from of_dma_set_restricted_buffer() when !OF_ADDRESS
swiotlb: add overflow checks to swiotlb_bounce
swiotlb: fix implicit debugfs declarations
of: Add plumbing for restricted DMA pool
dt-bindings: of: Add restricted DMA pool
swiotlb: Add restricted DMA pool initialization
swiotlb: Add restricted DMA alloc/free support
swiotlb: Refactor swiotlb_tbl_unmap_single
swiotlb: Move alloc_size to swiotlb_find_slots
swiotlb: Use is_swiotlb_force_bounce for swiotlb data bouncing
swiotlb: Update is_swiotlb_active to add a struct device argument
swiotlb: Update is_swiotlb_buffer to add a struct device argument
...
Merge misc updates from Andrew Morton:
"173 patches.
Subsystems affected by this series: ia64, ocfs2, block, and mm (debug,
pagecache, gup, swap, shmem, memcg, selftests, pagemap, mremap,
bootmem, sparsemem, vmalloc, kasan, pagealloc, memory-failure,
hugetlb, userfaultfd, vmscan, compaction, mempolicy, memblock,
oom-kill, migration, ksm, percpu, vmstat, and madvise)"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (173 commits)
mm/madvise: add MADV_WILLNEED to process_madvise()
mm/vmstat: remove unneeded return value
mm/vmstat: simplify the array size calculation
mm/vmstat: correct some wrong comments
mm/percpu,c: remove obsolete comments of pcpu_chunk_populated()
selftests: vm: add COW time test for KSM pages
selftests: vm: add KSM merging time test
mm: KSM: fix data type
selftests: vm: add KSM merging across nodes test
selftests: vm: add KSM zero page merging test
selftests: vm: add KSM unmerge test
selftests: vm: add KSM merge test
mm/migrate: correct kernel-doc notation
mm: wire up syscall process_mrelease
mm: introduce process_mrelease system call
memblock: make memblock_find_in_range method private
mm/mempolicy.c: use in_task() in mempolicy_slab_node()
mm/mempolicy: unify the create() func for bind/interleave/prefer-many policies
mm/mempolicy: advertise new MPOL_PREFERRED_MANY
mm/hugetlb: add support for mempolicy MPOL_PREFERRED_MANY
...
There are a lot of uses of memblock_find_in_range() along with
memblock_reserve() from the times memblock allocation APIs did not exist.
memblock_find_in_range() is the very core of memblock allocations, so any
future changes to its internal behaviour would mandate updates of all the
users outside memblock.
Replace the calls to memblock_find_in_range() with an equivalent calls to
memblock_phys_alloc() and memblock_phys_alloc_range() and make
memblock_find_in_range() private method of memblock.
This simplifies the callers, ensures that (unlikely) errors in
memblock_reserve() are handled and improves maintainability of
memblock_find_in_range().
Link: https://lkml.kernel.org/r/20210816122622.30279-1-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> [arm64]
Acked-by: Kirill A. Shutemov <kirill.shtuemov@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> [ACPI]
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Acked-by: Nick Kossifidis <mick@ics.forth.gr> [riscv]
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "Introduce multi-preference mempolicy", v7.
This patch series introduces the concept of the MPOL_PREFERRED_MANY
mempolicy. This mempolicy mode can be used with either the
set_mempolicy(2) or mbind(2) interfaces. Like the MPOL_PREFERRED
interface, it allows an application to set a preference for nodes which
will fulfil memory allocation requests. Unlike the MPOL_PREFERRED mode,
it takes a set of nodes. Like the MPOL_BIND interface, it works over a
set of nodes. Unlike MPOL_BIND, it will not cause a SIGSEGV or invoke the
OOM killer if those preferred nodes are not available.
Along with these patches are patches for libnuma, numactl, numademo, and
memhog. They still need some polish, but can be found here:
https://gitlab.com/bwidawsk/numactl/-/tree/prefer-many It allows new
usage: `numactl -P 0,3,4`
The goal of the new mode is to enable some use-cases when using tiered memory
usage models which I've lovingly named.
1a. The Hare - The interconnect is fast enough to meet bandwidth and
latency requirements allowing preference to be given to all nodes with
"fast" memory.
1b. The Indiscriminate Hare - An application knows it wants fast
memory (or perhaps slow memory), but doesn't care which node it runs
on. The application can prefer a set of nodes and then xpu bind to
the local node (cpu, accelerator, etc). This reverses the nodes are
chosen today where the kernel attempts to use local memory to the CPU
whenever possible. This will attempt to use the local accelerator to
the memory.
2. The Tortoise - The administrator (or the application itself) is
aware it only needs slow memory, and so can prefer that.
Much of this is almost achievable with the bind interface, but the bind
interface suffers from an inability to fallback to another set of nodes if
binding fails to all nodes in the nodemask.
Like MPOL_BIND a nodemask is given. Inherently this removes ordering from the
preference.
> /* Set first two nodes as preferred in an 8 node system. */
> const unsigned long nodes = 0x3
> set_mempolicy(MPOL_PREFER_MANY, &nodes, 8);
> /* Mimic interleave policy, but have fallback *.
> const unsigned long nodes = 0xaa
> set_mempolicy(MPOL_PREFER_MANY, &nodes, 8);
Some internal discussion took place around the interface. There are two
alternatives which we have discussed, plus one I stuck in:
1. Ordered list of nodes. Currently it's believed that the added
complexity is nod needed for expected usecases.
2. A flag for bind to allow falling back to other nodes. This
confuses the notion of binding and is less flexible than the current
solution.
3. Create flags or new modes that helps with some ordering. This
offers both a friendlier API as well as a solution for more customized
usage. It's unknown if it's worth the complexity to support this.
Here is sample code for how this might work:
> // Prefer specific nodes for some something wacky
> set_mempolicy(MPOL_PREFER_MANY, 0x17c, 1024);
>
> // Default
> set_mempolicy(MPOL_PREFER_MANY | MPOL_F_PREFER_ORDER_SOCKET, NULL, 0);
> // which is the same as
> set_mempolicy(MPOL_DEFAULT, NULL, 0);
>
> // The Hare
> set_mempolicy(MPOL_PREFER_MANY | MPOL_F_PREFER_ORDER_TYPE, NULL, 0);
>
> // The Tortoise
> set_mempolicy(MPOL_PREFER_MANY | MPOL_F_PREFER_ORDER_TYPE_REV, NULL, 0);
>
> // Prefer the fast memory of the first two sockets
> set_mempolicy(MPOL_PREFER_MANY | MPOL_F_PREFER_ORDER_TYPE, -1, 2);
>
This patch (of 5):
The NUMA APIs currently allow passing in a "preferred node" as a single
bit set in a nodemask. If more than one bit it set, bits after the first
are ignored.
This single node is generally OK for location-based NUMA where memory
being allocated will eventually be operated on by a single CPU. However,
in systems with multiple memory types, folks want to target a *type* of
memory instead of a location. For instance, someone might want some
high-bandwidth memory but do not care about the CPU next to which it is
allocated. Or, they want a cheap, high capacity allocation and want to
target all NUMA nodes which have persistent memory in volatile mode. In
both of these cases, the application wants to target a *set* of nodes, but
does not want strict MPOL_BIND behavior as that could lead to OOM killer
or SIGSEGV.
So add MPOL_PREFERRED_MANY policy to support the multiple preferred nodes
requirement. This is not a pie-in-the-sky dream for an API. This was a
response to a specific ask of more than one group at Intel. Specifically:
1. There are existing libraries that target memory types such as
https://github.com/memkind/memkind. These are known to suffer from
SIGSEGV's when memory is low on targeted memory "kinds" that span more
than one node. The MCDRAM on a Xeon Phi in "Cluster on Die" mode is an
example of this.
2. Volatile-use persistent memory users want to have a memory policy
which is targeted at either "cheap and slow" (PMEM) or "expensive and
fast" (DRAM). However, they do not want to experience allocation
failures when the targeted type is unavailable.
3. Allocate-then-run. Generally, we let the process scheduler decide
on which physical CPU to run a task. That location provides a default
allocation policy, and memory availability is not generally considered
when placing tasks. For situations where memory is valuable and
constrained, some users want to allocate memory first, *then* allocate
close compute resources to the allocation. This is the reverse of the
normal (CPU) model. Accelerators such as GPUs that operate on
core-mm-managed memory are interested in this model.
A check is added in sanitize_mpol_flags() to not permit 'prefer_many'
policy to be used for now, and will be removed in later patch after all
implementations for 'prefer_many' are ready, as suggested by Michal Hocko.
[mhocko@kernel.org: suggest to refine policy_node/policy_nodemask handling]
Link: https://lkml.kernel.org/r/1627970362-61305-1-git-send-email-feng.tang@intel.com
Link: https://lore.kernel.org/r/20200630212517.308045-4-ben.widawsky@intel.com
Link: https://lkml.kernel.org/r/1627970362-61305-2-git-send-email-feng.tang@intel.com
Co-developed-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Feng Tang <feng.tang@intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>b
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The proactive compaction[1] gets triggered for every 500msec and run
compaction on the node for COMPACTION_HPAGE_ORDER (usually order-9) pages
based on the value set to sysctl.compaction_proactiveness. Triggering the
compaction for every 500msec in search of COMPACTION_HPAGE_ORDER pages is
not needed for all applications, especially on the embedded system
usecases which may have few MB's of RAM. Enabling the proactive
compaction in its state will endup in running almost always on such
systems.
Other side, proactive compaction can still be very much useful for getting
a set of higher order pages in some controllable manner(controlled by
using the sysctl.compaction_proactiveness). So, on systems where enabling
the proactive compaction always may proove not required, can trigger the
same from user space on write to its sysctl interface. As an example, say
app launcher decide to launch the memory heavy application which can be
launched fast if it gets more higher order pages thus launcher can prepare
the system in advance by triggering the proactive compaction from
userspace.
This triggering of proactive compaction is done on a write to
sysctl.compaction_proactiveness by user.
[1]https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=facdaa917c4d5a376d09d25865f5a863f906234a
[akpm@linux-foundation.org: tweak vm.rst, per Mike]
Link: https://lkml.kernel.org/r/1627653207-12317-1-git-send-email-charante@codeaurora.org
Signed-off-by: Charan Teja Reddy <charante@codeaurora.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nitin Gupta <nigupta@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Khalid Aziz <khalid.aziz@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some method is obviously needed to enable reclaim-based migration.
Just like traditional autonuma, there will be some workloads that will
benefit like workloads with more "static" configurations where hot pages
stay hot and cold pages stay cold. If pages come and go from the hot and
cold sets, the benefits of this approach will be more limited.
The benefits are truly workload-based and *not* hardware-based. We do not
believe that there is a viable threshold where certain hardware
configurations should have this mechanism enabled while others do not.
To be conservative, earlier work defaulted to disable reclaim- based
migration and did not include a mechanism to enable it. This proposes add
a new sysfs file
/sys/kernel/mm/numa/demotion_enabled
as a method to enable it.
We are open to any alternative that allows end users to enable this
mechanism or disable it if workload harm is detected (just like
traditional autonuma).
Once this is enabled page demotion may move data to a NUMA node that does
not fall into the cpuset of the allocating process. This could be
construed to violate the guarantees of cpusets. However, since this is an
opt-in mechanism, the assumption is that anyone enabling it is content to
relax the guarantees.
Link: https://lkml.kernel.org/r/20210721063926.3024591-9-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20210715055145.195411-10-ying.huang@intel.com
Signed-off-by: Huang Ying <ying.huang@intel.com>
Originally-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "userfaultfd: minor bug fixes".
Three unrelated bug fixes. The first two addresses possible issues (not
too theoretical ones), but I did not encounter them in practice.
The third patch addresses a test bug that causes the test to fail on my
system. It has been sent before as part of a bigger RFC.
This patch (of 3):
mmap_changing is currently a boolean variable, which is set and cleared
without any lock that protects against concurrent modifications.
mmap_changing is supposed to mark whether userfaultfd page-faults handling
should be retried since mappings are undergoing a change. However,
concurrent calls, for instance to madvise(MADV_DONTNEED), might cause
mmap_changing to be false, although the remove event was still not read
(hence acknowledged) by the user.
Change mmap_changing to atomic_t and increase/decrease appropriately. Add
a debug assertion to see whether mmap_changing is negative.
Link: https://lkml.kernel.org/r/20210808020724.1022515-1-namit@vmware.com
Link: https://lkml.kernel.org/r/20210808020724.1022515-2-namit@vmware.com
Fixes: df2cc96e77 ("userfaultfd: prevent non-cooperative events vs mcopy_atomic races")
Signed-off-by: Nadav Amit <namit@vmware.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Guillaume Morin reported hitting the following WARNING followed by GPF or
NULL pointer deference either in cgroups_destroy or in the kill_css path.:
percpu ref (css_release) <= 0 (-1) after switching to atomic
WARNING: CPU: 23 PID: 130 at lib/percpu-refcount.c:196 percpu_ref_switch_to_atomic_rcu+0x127/0x130
CPU: 23 PID: 130 Comm: ksoftirqd/23 Kdump: loaded Tainted: G O 5.10.60 #1
RIP: 0010:percpu_ref_switch_to_atomic_rcu+0x127/0x130
Call Trace:
rcu_core+0x30f/0x530
rcu_core_si+0xe/0x10
__do_softirq+0x103/0x2a2
run_ksoftirqd+0x2b/0x40
smpboot_thread_fn+0x11a/0x170
kthread+0x10a/0x140
ret_from_fork+0x22/0x30
Upon further examination, it was discovered that the css structure was
associated with hugetlb reservations.
For private hugetlb mappings the vma points to a reserve map that
contains a pointer to the css. At mmap time, reservations are set up
and a reference to the css is taken. This reference is dropped in the
vma close operation; hugetlb_vm_op_close. However, if a vma is split no
additional reference to the css is taken yet hugetlb_vm_op_close will be
called twice for the split vma resulting in an underflow.
Fix by taking another reference in hugetlb_vm_op_open. Note that the
reference is only taken for the owner of the reserve map. In the more
common fork case, the pointer to the reserve map is cleared for
non-owning vmas.
Link: https://lkml.kernel.org/r/20210830215015.155224-1-mike.kravetz@oracle.com
Fixes: e9fe92ae0c ("hugetlb_cgroup: add reservation accounting for private mappings")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Guillaume Morin <guillaume@morinfr.org>
Suggested-by: Guillaume Morin <guillaume@morinfr.org>
Tested-by: Guillaume Morin <guillaume@morinfr.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In the current implementation of soft offline, if non-LRU page is met,
all the slab caches will be dropped to free the page then offline. But
if the page is not slab page all the effort is wasted in vain. Even
though it is a slab page, it is not guaranteed the page could be freed
at all.
However the side effect and cost is quite high. It does not only drop
the slab caches, but also may drop a significant amount of page caches
which are associated with inode caches. It could make the most
workingset gone in order to just offline a page. And the offline is not
guaranteed to succeed at all, actually I really doubt the success rate
for real life workload.
Furthermore the worse consequence is the system may be locked up and
unusable since the page cache release may incur huge amount of works
queued for memcg release.
Actually we ran into such unpleasant case in our production environment.
Firstly, the workqueue of memory_failure_work_func is locked up as
below:
BUG: workqueue lockup - pool cpus=1 node=0 flags=0x0 nice=0 stuck for 53s!
Showing busy workqueues and worker pools:
workqueue events: flags=0x0
pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=14/256 refcnt=15
in-flight: 409271:memory_failure_work_func
pending: kfree_rcu_work, kfree_rcu_monitor, kfree_rcu_work, rht_deferred_worker, rht_deferred_worker, rht_deferred_worker, rht_deferred_worker, kfree_rcu_work, kfree_rcu_work, kfree_rcu_work, kfree_rcu_work, drain_local_stock, kfree_rcu_work
workqueue mm_percpu_wq: flags=0x8
pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/256 refcnt=2
pending: vmstat_update
workqueue cgroup_destroy: flags=0x0
pwq 2: cpus=1 node=0 flags=0x0 nice=0 active=1/1 refcnt=12072
pending: css_release_work_fn
There were over 12K css_release_work_fn queued, and this caused a few
lockups due to the contention of worker pool lock with IRQ disabled, for
example:
NMI watchdog: Watchdog detected hard LOCKUP on cpu 1
Modules linked in: amd64_edac_mod edac_mce_amd crct10dif_pclmul crc32_pclmul ghash_clmulni_intel xt_DSCP iptable_mangle kvm_amd bpfilter vfat fat acpi_ipmi i2c_piix4 usb_storage ipmi_si k10temp i2c_core ipmi_devintf ipmi_msghandler acpi_cpufreq sch_fq_codel xfs libcrc32c crc32c_intel mlx5_core mlxfw nvme xhci_pci ptp nvme_core pps_core xhci_hcd
CPU: 1 PID: 205500 Comm: kworker/1:0 Tainted: G L 5.10.32-t1.el7.twitter.x86_64 #1
Hardware name: TYAN F5AMT /z /S8026GM2NRE-CGN, BIOS V8.030 03/30/2021
Workqueue: events memory_failure_work_func
RIP: 0010:queued_spin_lock_slowpath+0x41/0x1a0
Code: 41 f0 0f ba 2f 08 0f 92 c0 0f b6 c0 c1 e0 08 89 c2 8b 07 30 e4 09 d0 a9 00 01 ff ff 75 1b 85 c0 74 0e 8b 07 84 c0 74 08 f3 90 <8b> 07 84 c0 75 f8 b8 01 00 00 00 66 89 07 c3 f6 c4 01 75 04 c6 47
RSP: 0018:ffff9b2ac278f900 EFLAGS: 00000002
RAX: 0000000000480101 RBX: ffff8ce98ce71800 RCX: 0000000000000084
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff8ce98ce6a140
RBP: 00000000000284c8 R08: ffffd7248dcb6808 R09: 0000000000000000
R10: 0000000000000003 R11: ffff9b2ac278f9b0 R12: 0000000000000001
R13: ffff8cb44dab9c00 R14: ffffffffbd1ce6a0 R15: ffff8cacaa37f068
FS: 0000000000000000(0000) GS:ffff8ce98ce40000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcf6e8cb000 CR3: 0000000a0c60a000 CR4: 0000000000350ee0
Call Trace:
__queue_work+0xd6/0x3c0
queue_work_on+0x1c/0x30
uncharge_batch+0x10e/0x110
mem_cgroup_uncharge_list+0x6d/0x80
release_pages+0x37f/0x3f0
__pagevec_release+0x1c/0x50
__invalidate_mapping_pages+0x348/0x380
inode_lru_isolate+0x10a/0x160
__list_lru_walk_one+0x7b/0x170
list_lru_walk_one+0x4a/0x60
prune_icache_sb+0x37/0x50
super_cache_scan+0x123/0x1a0
do_shrink_slab+0x10c/0x2c0
shrink_slab+0x1f1/0x290
drop_slab_node+0x4d/0x70
soft_offline_page+0x1ac/0x5b0
memory_failure_work_func+0x6a/0x90
process_one_work+0x19e/0x340
worker_thread+0x30/0x360
kthread+0x116/0x130
The lockup made the machine is quite unusable. And it also made the
most workingset gone, the reclaimabled slab caches were reduced from 12G
to 300MB, the page caches were decreased from 17G to 4G.
But the most disappointing thing is all the effort doesn't make the page
offline, it just returns:
soft_offline: 0x1469f2: unknown non LRU page type 5ffff0000000000 ()
It seems the aggressive behavior for non-LRU page didn't pay back, so it
doesn't make too much sense to keep it considering the terrible side
effect.
Link: https://lkml.kernel.org/r/20210819054116.266126-1-shy828301@gmail.com
Signed-off-by: Yang Shi <shy828301@gmail.com>
Reported-by: David Mackey <tdmackey@twitter.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently SECTION_NID_SHIFT is set to 3, which is incorrect because bit 3
and 4 can be overlapped by sub-field for early NID, and can be
unexpectedly set on NUMA systems. There are a few non-critical issues
related to this:
- Having SECTION_TAINT_ZONE_DEVICE set for wrong sections forces
pfn_to_online_page() through the slow path, but doesn't actually break
the kernel.
- A kdump generation tool like makedumpfile uses this field to calculate
the physical address to read. So wrong bits can make the tool access to
wrong address and fail to create kdump. This can be avoided by the
tool, so it's not critical.
To fix it, set SECTION_NID_SHIFT to 6 which is the minimum number of
available bits of section flag field.
Link: https://lkml.kernel.org/r/20210707045548.810271-1-naoya.horiguchi@linux.dev
Fixes: 1f90a3477d ("mm: teach pfn_to_online_page() about ZONE_DEVICE section collisions")
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Kazuhito Hagio <k-hagio-ab@nec.com>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wang Wensheng <wangwensheng4@huawei.com>
Cc: Rui Xiang <rui.xiang@huawei.com>
Cc: Kazu <k-hagio-ab@nec.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At the moment memcg stats are read in four contexts:
1. memcg stat user interfaces
2. dirty throttling
3. page fault
4. memory reclaim
Currently the kernel flushes the stats for first two cases. Flushing the
stats for remaining two casese may have performance impact. Always
flushing the memcg stats on the page fault code path may negatively
impacts the performance of the applications. In addition flushing in the
memory reclaim code path, though treated as slowpath, can become the
source of contention for the global lock taken for stat flushing because
when system or memcg is under memory pressure, many tasks may enter the
reclaim path.
This patch uses following mechanisms to solve these challenges:
1. Periodically flush the stats from root memcg every 2 seconds. This
will time limit the out of sync stats.
2. Asynchronously flush the stats after fixed number of stat updates.
In the worst case the stat can be out of sync by O(nr_cpus * BATCH) for
2 seconds.
3. For avoiding thundering herd to flush the stats particularly from
the memory reclaim context, introduce memcg local spinlock and let only
one flusher active at a time. This could have been done through
cgroup_rstat_lock lock but that lock is used by other subsystem and for
userspace reading memcg stats. So, it is better to keep flushers
introduced by this patch decoupled from cgroup_rstat_lock. However we
would have to use irqsafe version of rstat flush but that is fine as
this code path will be flushing for whole tree and do the work for
everyone. No one will be waiting for that worker.
[shakeelb@google.com: fix sleep-in-wrong context bug]
Link: https://lkml.kernel.org/r/20210716212137.1391164-2-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210714013948.270662-2-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The commit 2d146aa3aa ("mm: memcontrol: switch to rstat") switched memcg
stats to rstat infrastructure but skipped the conversion of the lruvec
stats as such stats are read in the performance critical code paths and
flushing stats may have impacted the performances of the applications.
This patch converts the lruvec stats to rstat and later patches add
mechanisms to keep the performance impact to minimum.
The rstat conversion comes with the price i.e. memory cost. Effectively
this patch reverts the savings done by the commit f3344adf38 ("mm:
memcontrol: optimize per-lruvec stats counter memory usage"). However
this cost is justified due to negative impact of the inaccurate lruvec
stats on many heuristics. One such case is reported in [1].
The memory reclaim code is filled with plethora of heuristics and many of
those heuristics reads the lruvec stats. So, inaccurate stats can make
such heuristics ineffective. [1] reports the impact of inaccurate lruvec
stats on the "cache trim mode" heuristic. Inaccurate lruvec stats can
impact the deactivation and aging anon heuristics as well.
[1] https://lore.kernel.org/linux-mm/20210311004449.1170308-1-ying.huang@intel.com/
Link: https://lkml.kernel.org/r/20210716212137.1391164-1-shakeelb@google.com
Link: https://lkml.kernel.org/r/20210714013948.270662-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Extend shmem_huge_enabled(vma) to shmem_is_huge(vma, inode, index), so
that a consistent set of checks can be applied, even when the inode is
accessed through read/write syscalls (with NULL vma) instead of mmaps (the
index argument is seldom of interest, but required by mount option
"huge=within_size"). Clean up and rearrange the checks a little.
This then replaces the checks which shmem_fault() and shmem_getpage_gfp()
were making, and eliminates the SGP_HUGE and SGP_NOHUGE modes.
Replace a couple of 0s by explicit SHMEM_HUGE_NEVERs; and replace the
obscure !shmem_mapping() symlink check by explicit S_ISLNK() - nothing
else needs that symlink check, so leave it there in shmem_getpage_gfp().
Link: https://lkml.kernel.org/r/23a77889-2ddc-b030-75cd-44ca27fd4d1@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
khugepaged's collapse_file() currently uses SGP_NOHUGE to tell
shmem_getpage() not to try allocating a huge page, in the very unlikely
event that a racing hole-punch removes the swapped or fallocated page as
soon as i_pages lock is dropped.
We want to consolidate shmem's huge decisions, removing SGP_HUGE and
SGP_NOHUGE; but cannot quite persuade ourselves that it's okay to regress
the protection in this case - Yang Shi points out that the huge page would
remain indefinitely, charged to root instead of the intended memcg.
collapse_file() should not even allocate a small page in this case: why
proceed if someone is punching a hole? SGP_READ is almost the right flag
here, except that it optimizes away from a fallocated page, with NULL to
tell caller to fill with zeroes (like a hole); whereas collapse_file()'s
sequence relies on using a cache page. Add SGP_NOALLOC just for this.
There are too many consecutive "if (page"s there in shmem_getpage_gfp():
group it better; and fix the outdated "bring it back from swap" comment.
Link: https://lkml.kernel.org/r/1355343b-acf-4653-ef79-6aee40214ac5@google.com
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A successful shmem_fallocate() guarantees that the extent has been
reserved, even beyond i_size when the FALLOC_FL_KEEP_SIZE flag was used.
But that guarantee is broken by shmem_unused_huge_shrink()'s attempts to
split huge pages and free their excess beyond i_size; and by other uses of
split_huge_page() near i_size.
It's sad to add a shmem inode field just for this, but I did not find a
better way to keep the guarantee. A flag to say KEEP_SIZE has been used
would be cheaper, but I'm averse to unclearable flags. The fallocend
field is not perfect either (many disjoint ranges might be fallocated),
but good enough; and gains another use later on.
Link: https://lkml.kernel.org/r/ca9a146-3a59-6cd3-7f28-e9a044bb1052@google.com
Fixes: 779750d20b ("shmem: split huge pages beyond i_size under memory pressure")
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Each CPU has SHMEM_INO_BATCH inodes available in `->ino_batch' which is
per-CPU. Access here is serialized by disabling preemption. If the pool
is empty, it gets reloaded from `->next_ino'. Access here is serialized
by ->stat_lock which is a spinlock_t and can not be acquired with disabled
preemption.
One way around it would make per-CPU ino_batch struct containing the inode
number a local_lock_t.
Another solution is to promote ->stat_lock to a raw_spinlock_t. The
critical sections are short. The mpol_put() must be moved outside of the
critical section to avoid invoking the destructor with disabled
preemption.
Link: https://lkml.kernel.org/r/20210806142916.jdwkb5bx62q5fwfo@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
try_get_page() is very similar to try_get_compound_head(), and in fact
try_get_page() has fallen a little behind in terms of maintenance:
try_get_compound_head() handles speculative page references more
thoroughly.
There are only two try_get_page() callsites, so just call
try_get_compound_head() directly from those, and remove try_get_page()
entirely.
Also, seeing as how this changes try_get_compound_head() into a non-static
function, provide some kerneldoc documentation for it.
Link: https://lkml.kernel.org/r/20210813044133.1536842-4-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently cgroup_writeback_by_id calls mem_cgroup_wb_stats() to get dirty
pages for a memcg. However mem_cgroup_wb_stats() does a lot more than
just get the number of dirty pages. Just directly get the number of dirty
pages instead of calling mem_cgroup_wb_stats(). Also
cgroup_writeback_by_id() is only called for best-effort dirty flushing, so
remove the unused 'nr' parameter and no need to explicitly flush memcg
stats.
Link: https://lkml.kernel.org/r/20210722182627.2267368-1-shakeelb@google.com
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michael Stapelberg has reported that for workload with short big spikes of
writes (GCC linker seem to trigger this frequently) the write throughput
is heavily underestimated and tends to steadily sink until it reaches
zero. This has rather bad impact on writeback throttling (causing
stalls). The problem is that writeback throughput estimate gets updated
at most once per 200 ms. One update happens early after we submit pages
for writeback (at that point writeout of only small fraction of pages is
completed and thus observed throughput is tiny). Next update happens only
during the next write spike (updates happen only from inode writeback and
dirty throttling code) and if that is more than 1s after previous spike,
we decide system was idle and just ignore whatever was written until this
moment.
Fix the problem by making sure writeback throughput estimate is also
updated shortly after writeback completes to get reasonable estimate of
throughput for spiky workloads.
[jack@suse.cz: avoid division by 0 in wb_update_dirty_ratelimit()]
Link: https://lore.kernel.org/lkml/20210617095309.3542373-1-stapelberg+linux@google.com
Link: https://lkml.kernel.org/r/20210713104716.22868-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: Michael Stapelberg <stapelberg+linux@google.com>
Tested-by: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
